Helicopter search light

Abstract

A helicopter search light comprises: a lighting arrangement, having at least one light source, the lighting arrangement having an adjustable light output; a light detector, which is configured for detecting light emitted by the at least one light source and reflected by the ground and/or at least one item on the ground and for providing a detection signal which is correlated to an amount of light detected; and a control unit which is configured for controlling the adjustable light output of the lighting arrangement of the helicopter search light depending on the detection signal provided by the light detector.

The invention claimed is: 
     
       1. A helicopter search light comprising
 a lighting arrangement, having at least one light source, the lighting arrangement having an adjustable light output; 
 a light detector, which is configured for detecting light emitted by the at least one light source and reflected by and at least one of the ground and at least one item on the ground and for providing a detection signal which is correlated to an amount of light detected; and 
 a control unit which is configured for controlling the adjustable light output of the lighting arrangement of the helicopter search light depending on the detection signal provided by the light detector, 
 wherein the lighting arrangement has a flood light mode and a spot light mode and wherein the lighting arrangement is switchable between the flood light mode and the spot light mode, and 
 wherein the control unit is configured for switching the lighting arrangement between the flood light mode and the spot light mode depending on the detection signal provided by the light detector. 
 
     
     
       2. The helicopter search light according to  claim 1 , wherein the lighting arrangement has at least one first light source, associated with the spot light mode, with the at least one first light source being dimmable and with the control unit controlling a dimming level of the at least one first light source depending on the detection signal provided by the light detector. 
     
     
       3. The helicopter search light according to  claim 2 , wherein the at least one first light source is a plurality of first light sources, with the control unit uniformly controlling the dimming level of the plurality of first light sources. 
     
     
       4. The helicopter search light according to  claim 1 , wherein the lighting arrangement has at least one second light source, associated with the flood light mode, with the at least one second light source being dimmable and with the control unit controlling a dimming level of the at least one second light source depending on the detection signal provided by the light detector. 
     
     
       5. The helicopter search light according to  claim 4 , wherein the at least one second light source is a plurality of second light sources, with the control unit uniformly controlling the dimming level of the plurality of second light sources. 
     
     
       6. The helicopter search light according to  claim 1 , wherein the control unit is configured for adjusting the adjustable light output of the lighting arrangement such that the amount of light detected by the light detector approaches a target value. 
     
     
       7. The helicopter search light according to  claim 1 , wherein a detection angle of the light detector is significantly smaller, in particular at least 10 times smaller, than a light emission angle of the lighting arrangement, wherein the detection angle of the light detector in particular is smaller or equal to 3°. 
     
     
       8. The search light system according to  claim 1 , wherein the light detector comprises at least one of a collimating lens and a parabolic reflector, with the at least one of the collimating lens and the parabolic reflector restricting the detection angle of the at least one light detector. 
     
     
       9. The helicopter search light according to  claim 1 , wherein the light detector is a luminance detector. 
     
     
       10. A method of adjusting a light output of a helicopter search light, with the helicopter search light having a lighting arrangement, comprising at least one light source and having an adjustable light output, wherein the method includes:
 emitting light from the lighting arrangement of the helicopter search light, 
 detecting light reflected by at least one of the ground and an item on the ground and providing a detection signal which is correlated to an amount of light detected; and 
 controlling the adjustable light output of the lighting arrangement of the helicopter search light depending on the detection signal, 
 wherein the step of controlling the adjustable light output of the lighting arrangement of the helicopter search light includes switching the lighting arrangement between a flood light mode and a spot light mode. 
 
     
     
       11. The method according to  claim 10 , wherein the lighting arrangement of the helicopter search light comprises at least one first light source, associated with the spot light mode, and at least one second light source, associated with the flood light mode, and wherein the step of controlling the adjustable light output of the lighting arrangement of the helicopter search light comprises at least one of:
 dimming the at least one first light source depending on the detection signal, and 
 dimming the at least one second light source depending on the detection signal. 
 
     
     
       12. The method according to any of  claim 10 , wherein the step of detecting light reflected by at least one of the ground and an item on the ground includes performing a luminance measurement.